BGP load sharing ?

[fileas]

Hi,

got a customers who's connected to one of our PE using 2 links.

2 BGP sessions have been set (we can't peer on loopbacks), the ebgp multipath option is set, I seen the same routes twice with equal cost on my PE, but customers report that one link is at 80% of usage whereas the other rarely goes up to 20%.

Cef is configue "per destination".

Can't see why I have this behaviour except that someone on customer routeur is running heavy traffic TCP soft like P2P.

Are there some caveheats on "loadsharing" with BGP on MPLS VPN architectures ?

Thanks

[didyap]

If you are using per-destination load balancing, then load sharing will depend on the destinations cached on each link You should probably try per packet load balancing and check.

[mheusinger]

Hi,

did you see 2 IP routes on remote PEs as well?

You might run into one problem coming from BGP maximum path for iBGP being 1 by default.

So you could try

router bgp 65000

addressfamily ipv4 vrf MyVRF

maximum-path ibgp 2

on all REMOTE PE, as they are learning the redundant CE routes through iMBGP and will not install both into the VRF routing table.

If you have route reflectors in place, then you will need to have different RD on the two VRFs the redundant CE interfaces are bound to.

Additionally on all remote PEs:

router bgp 65000

addressfamily ipv4 vrf MyVRF

maximum-path ibgp 2 import 2

egards

Martin